1. Field of the Invention
The invention relates to eyeglasses with interchangeable lenses.
2. Description of the Related Art
Eyeglasses having exchangeable lenses or lens assemblies offer several advantages over conventional eyeglasses having fixed lenses. For example, in the case of sunglasses, different pairs of lenses can be provided for varying light conditions. Examples of these lenses are preferably polarized to protect the eyes against ultraviolet rays and reduce glare. In the case of prescription glasses, lenses manufactured to the current prescription of the wearer can be easily exchanged for the out-of-date prescription lenses. Also, in the case of lens and/or frame damage, a single component can be replaced more economically than purchasing an entirely new pair of eyeglasses.
Exchangeable lens eyeglasses have been known for some time but older configurations have had significant shortcomings in that they are generally mechanically complex, making them expensive to manufacture. Other configurations require substantial mutual deformation of the lens and the front component of the frame making insertion and removal of a lens cumbersome and difficult.
Recently introduced exchangeable eyeglass designs have overcome these shortcomings by making replacement of the lenses convenient. In one structure disclosed in U.S. Pat. No. 4,176,921, the eyeglass front is disclosed as being made of wire with complete rims (rims completely encompassing the lenses). Soldered to the wire rims are two spaced lower prongs for supporting each lens. An additional prong extends adjacent the temple piece, and is either integral with the rim, or is secured in another soldered joint. The lenses, which are stored without a frame until ready for use, are inserted from above until they are embraced by the prongs. A metal lever is hinged to the bridge joining the rims and carries a prong for each lens. The lever is rotated downwardly to a holding position, to prevent upward movement of the lenses. Separate plastic nose pads are attached to the wire front. The eyeglasses shown in this patent have met with widespread success but they are relatively expensive due to the complete wire front, which is typically formed of a wire stock, and must be soldered in a separate manufacturing step to form a closed loop. Also, a complete wire rim is limited in its ability to accommodate designer materials and colors.
Complete wire rims, especially those for mating with exchangeable lenses can present a problem in that the wire rims are susceptible to bending or other deformation, which destroys the relatively close-tolerance lens-conforming configuration. Also, the lenses themselves are unsupported during storage. Plastic and polycarbonate lenses may tend to warp if stored under conditions of excessive heat or pressure and can also scratch relatively easily.
An eyeglass configuration for a front assembly having partial rims (rims which extend about the periphery of typically only the upper or lower portion of the lenses) is disclosed in U.S. Pat. No. 4,523,819. The eyeglass front includes wires or threads that are received in grooves in the exposed bottom edges of the lenses. The threads are fastened to one end of their associated partial rim and meet at the bridge section of the front where their remaining ends are held by the free ends of pivotal levers for tensioning the threads. A retainer clip, which is hinged to a lower bridge member, overlies the lever free ends to maintain the levers in their tensioning positions. The front used in the eyeglasses is preferably formed of metal to accommodate the wear occasioned by the use of pivoting components, to permit the attachment of prongs, and to provide adequate strength for tensioning. While generally satisfactory, the eyeglasses shown in this patent present some difficulties for wearers who have limited manual dexterity or who are engaged in outdoor winter sports or other activities requiring gloves.
Another embodiment of an interchangeable eyeglass configuration is shown in U.S. Pat. No. 2,738,709. An eyeglass frame made of wire is provided for mounting two lenses, and includes an intermediate metal bridge portion. The wire frame is adapted to be received behind an overlying plastic frame containing the customary temple pieces for engaging the temples and ears of a wearer. Both the wire frame and the overlying plastic frame have complete rims that completely encircle the lenses. Recesses are provided in the rear of the overlying plastic frame (adjacent the wearer's face), to receive the entire rim portions of the wire frame. Two hingeable latches are provided on the overlying plastic frame adjacent the temple pieces to secure the wire frame thereto. This interchangeable eyeglass configuration has considerable mass (i.e. bulk) and is therefore relatively heavy. The overlying plastic frame must be sufficiently bulky at its bridge and rim portions to hide or mask the underlying wire frame, and the front of the overlying plastic frame has enlarged bulk adjacent its temple portions to accommodate the separately formed hingeable latches. This configuration relies on frictional engagement between the wire and plastic bridges, which are susceptible to wear over years of use. To compensate for this wear, the temple pieces can be adjusted to increase pressure on the wearer's ear, thereby pressing the bridge portions together, but this may be uncomfortable over extended wearing times.
Eyeglasses with interchangeable lenses are known in the prior art. Examples include U.S. Pat. Nos. 4,759,622, 4,822,158, and 4,834,523. These patents use mechanical closures or clasps to lock the lenses in place. The mechanical clasp wears with usage. Eventually mechanical clasps wear to the point of not locking. This leads to the interchangeable lens not being locked in the eyeglasses allowing it to unintentionally fall out.
Another problem with mechanical claps is that they require physical force to lock and unlock them. For a secure hold, the amount of force may be enough to crack or chip the lens if the force is accidentally transferred to the lens. Accordingly, a clumsy effort to lock or unlock the bridge could lead to enough force to damage the lens to be brought onto lens.
Kidouchim, US. Patent Application No. US 2005/0052613, and Kidouchim, U.S. Pat. No. 6,869,180, show a system for attaching auxiliary lenses to an eyeframe that includes customary, non-removable primary lenses. A hinge is included to pivot the auxiliary lens into and out of position with the primary lens. The hinge does not release the primary lens. While a magnet is included to hold the auxiliary lenses in different positions 68 and 70, the application does not teach to use the magnet to lock a bridge closed so as to prevent the primary lenses from accidentally falling from the eyeframe.
In U.S. Pat. No. 6,789,893, Hong discloses a magnetically attached auxiliary lens system. The auxiliary lenses swivel on a hinge. The magnets are used to attach the support to the eyeframe not to lock the lenses in position.
In U.S. Pat. No. 6,637,878, Huang teaches a pivoting auxiliary lens system that is attached magnetically to a pair of eyeglasses. Huang does not show a hinged bridge that magnetically closes to hold a set of interchangeable primary lenses.
In U.S. Pat. Nos. 6,604,822 and 6,283,591, Chen teaches a pivoting auxiliary lens that attaches magnetically to a pair of eyeglasses. Chen does not show a hinged bridge that magnetically closes to hold a primary set of interchangeable lenses.
In U.S. Pat. No. 6,352,342, Huang teaches a pivoting auxiliary lens that attaches magnetically to a pair of eyeglasses. Huang does not show a hinged bridge that magnetically closes to hold a primary set of interchangeable lenses.
In U.S. Pat. No. 5,048,944, Porsche teaches eyeglasses with interchangeable primary lenses. The eyeglasses include a rimwire, a nose bridge, and a hinged closure. The retaining clip closes mechanically by snapping into place. The mechanical closure is subject to wear and, as the retaining clip become permanently deformed, the retaining clip will fail to retain the lenses.
In U.S. Pat. No. 4,176,921, Matthias teaches eyeglasses with interchangeable primary lenses. The eyeglasses include a rimwire, a nose bridge, and a hinged closure. The retaining clip closes mechanically by snapping into place. The mechanical closure is subject to wear and, as the retaining clip become permanently deformed, the retaining clip will fail to retain the lenses.
In U.S. Pat. No. 6,869,179, Friedman teaches a mechanical clip for attaching an auxiliary lens to eyeglasses. In U.S. Pat. No. 6,866,384, Madison teaches a magnetic attachment for auxiliary lenses to primary eyeglasses. In U.S. Pat. No. 6,478,420, Xiang teaches magnetic attachments that allow rimless auxiliary lenses to be attached to rimless primary lenses.
In U.S. Pat. No. 4,523,819, Dianitsch et al. improve the Porsche design and adds a ratcheted wire partially around the perimeter of the lenses to secure them.
In U.S. Patent No. Porsche U.S. Pat. No. 4,834,523, Porsche teaches collapsible eyewear with interchangeable primary lenses. Each lens has a plurality of notches that hold the lenses. The frame opens at a hinge at the stem.
In U.S. Pat. No. 4,822,158, Porsche teaches an interchangeable primary lens that attaches to a frame by a hinged bridge that mechanically closes. Porsche '158 does not teach a magnetic closure on the bridge.
In U.S. Pat. No. 4,759,622, Scmidthaler teaches a mechanical snapping bridge piece that releases interchangeable primary lenses. The bridge piece is not hinged. No magnetic closure is taught-just a snap.
Prior-art examples that include magnets fail to hide the magnets. That is, the magnets that attach auxiliary lenses are visible. These magnets, when visible, disturb the aesthetic norm of eyeglass frames that typically have no magnets visible. Accordingly, a need exists for eyeframes with interchangeable lenspieces that attach magnetically with magnets that are not visible.